Problem: Which of these numbers is composite? ${11,\ 35,\ 41,\ 61,\ 73}$
A composite number is a number that has more than two factors (including 1 and itself). 11, 41, 61, and 73 each have only two factors. The factors of 35 are 1, 5, 7, and 35. Thus, 35 is the composite number.